Amid constant climatic risks associated with El Niño, South African farmers are increasingly adopting precision agriculture tools to reduce resource costs without compromising yield. Dr. Michael Southwood, founder of the Agri Vision Foundation and organizer of the SADC Plant Nutrition Symposium, explains how precision measurement tools help decrease water and fertilizer consumption while protecting long-term soil health.
Modern precision farming has moved beyond being a process of expensive guesswork; it is now focused on actionable real-time data that directly influences daily management decisions.
When optimizing irrigation, Southwood asserts that water management essentially boils down to controlling oxygen levels in the root zone. Overwatering saturates the top 30–40 centimeters of soil where most nutrient roots are located, creating anaerobic conditions that inhibit root development and soil biological activity. Southwood warns: 'If you overwater, there will obviously be a lack of oxygen, and you won't have continuous new root formation.'
By using soil moisture sensors at different depths of 10 cm, as well as drone technology and NDVI satellite imagery, producers can accurately monitor soil water retention capacity and detect early signs of crop stress even before visible symptoms appear.
Excessive nitrogen application remains a common and costly problem in commercial crop production. Southwood notes that about seven out of ten crop quality issues arise from nitrogen excess, which promotes soft, lush growth, making plants vulnerable to biotic and abiotic stress.
Instead of relying solely on laboratory analysis of dry leaves, which often reflects past nutritional history, Southwood advises using handheld sap meters to track nitrogen, electrical conductivity (EC), and Brix levels twice a week directly in the field. He explains: 'You can actually squeeze the juice from fruits or leaf petioles on site, in real time, and this will allow you to determine the plant's nutritional composition in the juice.'
Real-time sap monitoring allows farmers to continuously adjust nitrogen application, enabling operations to reduce the total volume of resources applied without decreasing crop quality or volume.
Modern resource management is shifting from large-scale application across entire hectares to targeted placement. By using advanced drip irrigation technologies or controlled-release formulations, producers can concentrate nutrients on only 15–20% of the field surface. This localized approach prevents soil salinization, minimizes long-term soil acidification, and preserves soil microflora health.
Southwood emphasizes that farmers wishing to implement precision agriculture practices should start small, selecting one well-performing plot and building their own dataset to guide future applications. He invites industry professionals to attend the upcoming SADC Plant Nutrition Symposium to delve deeper into these advanced application methods and technologies. He urges: 'If you want to learn more, you should join our fertilizer symposium,' noting that the event will feature technical presentations on advanced drip technology and precise fertilizer formulations.
The SADC Plant Nutrition Symposium will take place on Thursday, November 19, and Friday, November 20, 2026, at the Protea Hotel, Technopark, Stellenbosch, with online access available for regional delegates. To book places or request the program, please contact Marilise Kotsi at Symposium@southerncrosstrust.com or via WhatsApp at 082 261 1598.